Gear lapping machine



GEAR LAPPING MACHINE INVENTOR Fr/76,5? f7. OVerJ fed?.

TTORNEYS.

`Mau-ch 3, 1936. E, A. ovERsTED-r GEAR LAPPING MACHINE Filed Aug. 7, 1935 6 Sheets-Shes?l 2 INVENTOR Ervan? Z rerdied 'BY v ATTORNEYS March 3, 1936. v E. A. ovERs'l-EDT v 2,032,589

GEAR LAPPING MACHINE Filed Aug. 7, 1953 6 Sheets-Sheet 3 INVENTOR frz? @5f f7. Orenfied ATTORNEYS' March 3, 1936. E. A. OVERSTEDT 2,032,589

GEAR LAPPING MACHINE TTORNEY.

E. A. OVERSTEDT GEAR LAPPING MACHINE March 3, 1936.

Filed Aug. 7, 1933 6 Sheets-Shea?l ATTORNEYS' .il gear to be lapped a predetermined number of Patented Mar. 3, 1936 l d i UNITED STATES PATENT OFFICE i GEAR LAPPING MACHINE Ernest A. Overstedt, Detroit, ltIich., assignor, by

mesne assignments, to Michigan Tool Company, a corporation of Delaware Application August 7, 1933, Serial N0. 683,979

11 Claims. (Cl. 51-26) My invention relates to machines and particumovable upwardly to permit the gear to be relarly to a machine for accurately finishing the moved from the centers which support the gear teeth of a gear after they have been machined in rotation and to permit a new gear to be into substantial form to true the gear teeth to serted. Upon pulling the lever the lap is moved 5 accurate predetermined dimension. v down into engagement with the gear, applying a Efforts have been made heretofore to accurately pressure through the gear to the other laps to finish gear teeth by' employing a suitable lapping retain them in intimate relation with the gear. tool and compound when operating in mesh with Accordingly, the main objects of my invention the gear by a method clearly illustrated in the are to provide a gear nishing machine with a 1o G. C. Carhart Patent No. 1,537,583, dated May 12, plurality of tools which may be mated with a gear 10 1925, and assigned to the assignee of the present and Which are driven by the geen against a brake invention. The present invention relates pripressure; t provide laps which are 0f the spiral manly to a new form of machine and method, extype when a spur gear is t0 be machined 0r spur lending the principles disclosed in the Carhart laps When a Spiral gear iS t0 be machined aS the l5 patent. case may be; to offsetting the laps so that the l5 It is Well known, that when operating gears in teeth thereof mate with the teeth of the gear so as mesh with each other in the presence of a lapping t0 effect a lateral slippage between the Sides 0f compound therebetween, unsatisfactory machintne teeth Ofihe laps and 'hOSe 0f the gear Which 'ing is eireeted because of the feet that no abreding Wlll machine uniformly from the crown to the root is produced on the pitch line of the teeth as no 0f the geel teeth; te further GffSei'f One 01 more 0f 20 slippage occurs between the surfaces of the mated the laps t0 Ineehine e relief 0n ine Side edges 0f teeth at this point. The Carhart patent had the gear teeth; to mount the laps for angular l solved this problem in a simple manner by om movement so that they may be offset at an angle setting a spiral gear on a spur lap or a spuigeaian amount conforming to the lead of the teeth of s on a spiral lap so as to effect a lateral slippage the gear when spiral gears are to be machined or 25 therebetween which machines an equal amount t0 the lead 0f the teeth 0f the lap When e Spill at all points from the crown, through the pitch gear is to be machined 'or to be further offset in une, to the root of the teeth relation thereto when a relief atthe ends of the The present machine utilizes this oliset printeeth is to b? machined? to provide mdveble means 3U ciple for effecting a lateral slippage between the for Supportmg on? of the laps-for rinsing the lap 30. lap and gear and utilizes a plurality of the laps out of contact withthe gear topermit the gear which are driven by the gear to be machined in to be removed and e new geef .Inserted 1n the the presence of brake pressure which may be machme and thereafter for moving the lap into regulated relative to the kind of gear and quality engagement Wlthihe gear t0 apply a pressure peof the work to be produced. tween the lluralliy 0f-1aps and the gear dunne 35 The laps are mounted so as to he'adjustable the machining operatlon; to .prov1de automatic angularly to mate with any type of spur or spiral means which may be set to suit a particular type gear and to be oiset further therefrom when de- Of work for Operatlng the geel' and lans a predeter` sirable. That is to say, when employing three inmednumbe? 0f @Unes 1n one dlleelOn and then 40 laps. have one set at one angle and the other set m 9j r'evese dlrectlen 0f .1n repeated eyele thereof 4o at ahciher angle slightly (imei-ent from that of as 1s desirable; to provide automatic means for the angle of the lead of the gear so as to produce stoppmg the majchme after any euch Cycle 0f a slope to the edges cf the gear teeth which is so 'mofementj andydn generell, t0 DI'OVlde 2- machlne desirable on gears moved longitudinally into mesh Which is Snnple 1n )Del'a'len and adJllStment and 4.3 with each other. This slight relief on the side which 1S unlversal 1n apphcatlon- 45 edges of the teeth permits the ready meshing of Otnel' ObJeCtS and features of my invention will one gear relative to another and produces quiet be either specifically pointed out or w1ll become shifting of transmission gears which are shifted @Ppe-rent When referring fOr a better'underexiauy. The machine is constructed to drive the standing 0f my lnventlen, t0 the fellowmg description taken in conjunction with the accomtimes in one direction and automatically shifting Danying drawings, Whelein l and repeating the operation in the opposite direc- Figure l is a perspective View of a finishing ma.- tion and further repeating the cycle if necessary Chine embdymg features 0f my 1n ent 10n, s,

and thereafter stopping the machine. One of Fig. 2 is a side view of the machine illustrated .is the lapping tools is mounted on a. head which ls in Fig., 1, with the motor omitted therefrom,

Fig. 3 is a front view of the structure illustrated in Fig. 2, with the motor mounted in position,

Fig. 4 is an enlarged front view, in elevation, of the gear box of the machine illustrated in Fig. 3, with the front broken away,

Fig. 5 is an enlarged sectional view of the structure illustrated in Fig. 4 taken on the line 5-5 thereof,

Fig. 6 is a sectional view of the structure illustrated in Fig. 4, taken on the line 6 6 thereof,

Fig. 7 is a sectional view of the structure ,illustrated in Fig. 6, taken on the line 1--1 thereof,

Fig. 8 is a sectional view of the structure illustrated in Fig. 6, taken on the line 8 8 thereof.

Fig. 9 is an enlarged sectional View of the structure illustrated in Fig. 4, taken on the line 9--9 thereof, and

Fig. 10 is an enlarged sectional view of the structure illustrated in Fig. 3, taken on the line III-I0 thereof. Referring to Figs. 1, 2 and 3, I have illustrated a machine bed I I consisting of a table supporting portion I2 which is at right angles to yoke supporting portions I3 and I4 upon which a yoke I5 of inverted U-shape is supported and secured by bolts vI6.` Suitable ways I1 are provided on the top of the table supporting portion I2 upon which a table I8 is disposed for horizontal reciprocal movement. Upon the table is mounted a fixed head stock I9 and a tail stock 2| which is adjustable on the table in spaced relation to the head stock. 'I'he head stock I9 is provided with a fixed center 22 having a revolvable gear 6I thereabout which causes the work to be rotated. The adjustable tail stock is provided with a center 23 which is adjustable relative to the tail stock for clamping the work between the centers.

I have illustrated a spiral gear 24 mounted between the centers and mated with a plurality of lapping tools 25 which are similar in construction, although it is within the purview of my invention to employ tools of different diameters or with modified tooth forms so as to provide different pressure angles relative to the pressure angles of the gear teeth. The tools 25 are mounted on arbors 26 which are attached to a brake mechanism (not shown) which is supported in a cylinder 21 mounted on an adjustable arm 23. The brake mechanism is so constructed, in the nature of veins or gears, as to operate a fluid provided in the reservoir within the cylinder to build up a pressure which may be adjusted through the regulation of the size of the orifice, to thereby apply a braking force to the arbors to produce a predetermined load on the teeth of the tools and gear.

A balance brake is preferably provided, that is to say, a brake operable about the periphery of the arbor to balance the force thereof to prevent the application of a pressure on one side of the arbor which would wear the bearing thereof an unequal amount. The brake is so constructed as to operate in both directions through the flow of fluid caused either by the veins or the gears, during either direction of movement of the arbor. 'Ihe adjustment of the orifice is effected through the adjustment of the element 29 and the amount of pressure is registered on a gauge 3I which is connected within the cylinder,

A. suitable scale 32 may be provided on the extension of the cylinder and arm, for indexing the arbor relative to the degree of angular offset relation of the lapping tool relative to the gear teeth, while suitable ways 33 are provided for supporting the arm to radially adjust the tools relative to the work. A suitable indexing scale may be provided on the arm relative to the yoke I5 or otherwise, for indexing the setting of the arm to have the tools disposed on a predetermined radius conforming to the radius of the gear to be lapped. A suitable lead screw 34 is provided for moving the arm on the ways by operating a suitable handle engaging the stub arbor 35 in extension of the lead screw and the radially disposed lands 36 thereof in the nature of a modified spanner wrench 31, as illustrated on the top of the machine, for adjusting the ,topmost tool relative to its support.

In this manner, all the lapping tools may be adjusted radially to converge upon the gear to be machined and at the same time adjusted angularly to a degree conforming to that of the teeth or slightly therefrom for a purpose referred to hereinbefore and which will be referred to hereinafter. A suitable indexing plug 36 may be prof vided in conjunction with the extending indexing scale 32 for checking the index in a well known manner. y

On the upper part, of the yoke I5 ways -4I are provided in which a brake mechanism and a tool are supported by means of a toggle link connectionl 42 operated by a handle 43 against a spring 44 which biases the tool upwardly. The toggle link 42 is illustrated as being in on center position and. it isonly necessary to push the handle 43 upwardly to brake the toggle and permit the tool to be moved upwardly to clear the gear 24 so that the longitudinally movable center 23 may be moved out of engagement with the shaft upon which the gear is mounted to permit the gear to be removed from the machine and a second gear to be inserted in its stead. Through is moved into engagement with the gear which is already in engagement with the other two'laps to apply a predetermined pressure thereto. Through the movement of the toggle 42 into center or aligned position, the handle 43 is retained in a downward position to maintain such pressure on the gear.

For effecting the longitudinal movement of the center 22,' I have provided a handle 46 operating a gear sector 41 in engagement with rack-like teeth 49 provided on a spindle 49 in which the center 23 is mounted in fixed relation to cause the spindle 49 and therefore the center 23 to be moved longitudinally toward or away from the center 22, as illustrated more clearly in Fig. 2. Through the counter-clockwise rotation of the handle 46 the spindle 49 and therefore the center 23 Ais moved to 'the left, as viewed in Fig. 2, to clamp the shaft of the gear between the centers, after which a handle 5I may be tightened to clamp the spindle and therefore the center in xed engaged relation.

In Fig. 10, I have illustrated the method of drivthe downward'movement of the handle 43 the tool ing the shaft and the gear 24 through the rota.-

tion of the lgear 6I about the center 22 effected through the rotation of a shaft 52 driven by a suitable' belt 53 off of a pulley 54 which is rotatably mounted in a bearing 55 on an arm 6 secured to the yoke I5 of the machine. The sha t 52 has a which extends outwardly therefrom to be revolved about the center 22 which engages a dog or pin on the shaft to cause the shaft to rotate about the centers 22 and 23. A suitable bearing 62 is provided between the head of the spindle 63 which supports the center 22 and the gear 6| to eliminate friction therebetween. As the table |8 is reciprocated backwardly and forwardly upon the ways the shaft 52 moves through the rotating pulley 54 to effect the operation of the gear 59 and therefore the gear'6l. In ,this manner the pin on the gear 6| is rotated to drive the shaft about the centers 22 and 23.

A motor illustrated in Figs. l and 3, is mounted on one end of the base frame having a pulley thereon which is connected by a belt 66 to a pulley 61 mounted on a shaft 68. The shaft 68 effects the reciprocation of the table, the reversal of the tools and the operation of suitable controls for actuating the reversing elements and for stopping the machine after a predetermined cycle of operation. The shaft 68, as viewed in Fig. 6, drives a gear 69 for operating through a gear 7|, a shaft 12 which drives through a belt and pulley connection '|3, a reversing and stop mechanism i4 which will be described more fully hereinafter.

The shaft 'l2 is provided with a gear l0 on its outer end which is connected with a gear l5, as i1- lustrated in Fig. 4, for driving a shaft E6 and a beveled pinion 71 which is secured thereto for driving a ring gear 18 controlling the operation of the reciprocating mechanism I9 which will be described more fully hereinafter.

The shaft 68 also drives a gear 8| which is in mesh with an idling gear 82 meshed with a gear 83 which is fixed to a shaft 84 for driving the shaft 84 in one direction when a clutch 85 connects the gear 8| to the shaft 68. An additional gear 86 is connected to the opposite end of the shaft 68 which, as illustrated in Fig. 8, is in mesh with a gear 81 also on the shaft 84 for operating the shaft in an opposite direction when a clutch 88 connects the gear 86 to the shaft. The shaft 84 is provided with a gear 89 on its outer end which meshes with a gear 90 on shaft 80 which extends through the base of the machine to drive a pulley 9| on the opposite side of the machine and to which the belt 53 is connected to operate the driving gear 6| which is disposed about the center 22.

Upon the rotation of the shaft 68 the control mechanism '|4 is actuated through the gears 69 and 1|, shaft l2 and the belt and pulley connection 13. This driving connection controls the direction of rotation of the work and effects the stopping of the machine after a predetermined cycle of operation. The operation of the shaft 68 rotates either the gear 8| or 86, as illustrated in Figs. 7 and 8 respectively, depending upon which l of the clutches 85 or 88 is actuated to' connect the gear to the shaft. The shaft 84 is rotated in one direction when the clutch 85 engages the gear 8| to the shaft and in the opposite direction of rotation when the clutch 88 connects the gear 86 to the shaft. In this manner the shaft is operatedin a clockwise or counter-clockwise direction for operating the work in one direction or the other direction by means of the belt 53 `and its associated pulleys.

A clutch operating arm 95 is pivoted at 92 and has a bifurcated end portion 93 which engages a slot 94 in a collar employed for shifting the clutch elements and 88 longitudinally of the shaft 68. A rod 96 is employed for rocking the lever about the pivot 92 for operating the clutches 85 and 88 for effecting the driving of the shaft 84 in one or the other direction as the case may be. The lever 95 has an aperture 91 therein through which a shaft 98 extends, the aperture being elongated to permit the rocking of the lever 95 about the pivot 92 without interference by the shaft 98. The purpose of the shaft will be explained hereinafter.

'I'he control mechanism I4 is operated by the belt and pulley 'i3 off of the shaft l2, which is illustrated enlarged in Fig. 5. The belt and pulley '|3 drives through a pulley |0| to operate the shaft |02 which is suitably supported in bearings |03 and |04. A gear |05 is mounted on the shaft |02 which drives a gear |06 which is mounted on a stub shaft |01 for rotation about the shaft |02 on bearings |08 and |09. The gear |08 is meshed Withtwo internal gears, fixed gear |0 and a rotatable gear having an odd number of teeth,

for example, the internal gear H0 may have 89 teeth while the internal gear may have 'i9 teeth to cause the gear to be advanced one tooth during one complete rotation of the gear |06 about the shaft |02. This differentialiconstruction provides a very slow movement to the gear relative to' the rotation of the shaft |02 thereby effecting a slow movement of the shift cams |00 and I2 which are mounted on the support ||3 of the gear and the stop elements ||4 which are likewise carried by the body portion ||3 through the supporting annular member ||5.

In Fig. 9, I have shown an enlarged sectional view of a portion of the control mechanism illustrated in Fig. 4, wherein through the rocking of a handle ||6 the shaft is rotated for moving the clutch shifting rod 96 longitudinally of its length. A projection ||8 is mounted on an arm which projects upwardly from the shaft i il and is disposed in the path of movement of the shift cams |00 and ||2 for rocking the shaft Hi rst in one direction and then in another through the engagement of the cams |00 and ||2 therewith. Any number of the elements |00 and ||2 may be disposed about the body portion ||3 spaced any distance apart for controlling the length of time between each reversal or shifting of the rod 96.

In a similar manner, any number of stop elements i4 may be disposed about the member i5 i to control the stopping of the machine after a predeterminednumber of alternations of the work. The stop elements i4 engage the extending arm |2|, as illustrated in Fig. 4, for'operating a stop lever |22 to pressa button |23 of the electric switch |24 for cutting off the current to the motor to stop the operation of the machine. A start lever |25 is likewise pivoted to the side of the machine having a projecting element in engagement with a start button |26 of the'switch for starting the machine upon the actuation of the lever |25.

For controlling the degree of reciprocation of the table |8 and for effecting such reciprocation, the ring gear i8 is mounted on a shaft |2| for effecting the rotation of a gear |28 which is ineshed with a large gear |29 supported on a hollow shaft |3| through which therod 98 extends. During the operation of the machine and the rotation of the ring gear 18, the gear |29 is driven in rotation. The side of the gear'is provided with a dove tail slot |32 in which a dove tailed arm |33 is mounted having a pin |34 thereon which engages a link |30 pivoted at |35 to a lever |36 which is pivotally mounted on a shaft |31 through a boss |38. The upper end of the lever |36 is pivoted by a pin |39 to a link |4| which is pivoted at |42 to the table I8. Upon the rotation of the gear |29 the adjustable pivot point |34 is rotated about the shaft |3| to carry the link |30 around therewith to cause the-lever |36 to be oscillated about the pivot |31 to move the link |4| substantially longitudinally through a small arc which, owing to its pivotal connection to the table |8. causes the table to be reciprocated on the Ways |1.

Referring to Fig. 4, it will be noted that the shaft 98 carries a beveled pinion |43 in engagement with a beveled gear |44 which gear is mounted for rotation in fixed position to operate a lead screw |45 which is carried by the dovetailed arm |33 and which, upon rotation of the beveled gears |43 and |44, causes the lead screw and therefore the dovetailed arm |33 to be moved radially of the gear |20. In this manner the position of the pivot |34 relative tothe central axis of the gear |29 may be adjusted exteriorly of the machine. By adjusting the pivot in this manner the degree of oscillation of the lever |36 and, therefore, the amount of' reciprocation to the table I8 is regulated from zero to an amount at least as great as the width of the tools 24. The object of reciprocating the table is to produce uniform wear across the surface of the tools and to increase the amount of maching lengthwise of the teeth. It will be noted that the shaft 98 extends out from the machine, above the motor and the arrows thereabove indicate the direction the shaft is to be turned to shorten or lengthen the stroke.

When a series of like gears are to be finished, the control mechanism is first adjusted to effect the required amount of machining, that is to say, the number of rotations in one direction are set and the number of rotations in a reverse direction and the number o-f times the cycle is repeated before the machine is to be stopped. 'I'hus prearranged adjustment is effected through the setting of the shift blocks |00 and ||2 and the stop element ||4. In this manner all of the gears will be treated exactly alike which is desirable for like gears, the desired number of operations to complete a cycle is found empirically and Will be substantially known from prior operation of the machine. After 'the "start lever is pushed to throw the switch, the gear and tools will operate a predetermined number of times in rotation in one direction during `.a relative reciprocation therebetween after which they may be reversed and run in the opposite direction and the cycle repeated a predetermined number of times until the stop element is automatically moved to throw the switch to off position to stop the operation of the machine. Thereafter the handle 43 is to permit the gear to be'removed and a new gear disposed in clamped relation to the centers. 'I'he handle 43 is then moved downwardly to niove the raised tool into engagement with the gear and to provide a pressure between the gear and tools and it is only necessary to again move the start lever to have the cycle of operation repeated to effect a complete machining of the gear.

As has, been pointed out hereinabove, the tools may be angularly disposed an amount equal to the angle of the gear teeth when a spiral gear is to be machined or when spiral tools are utilized and a spur gear to be machined, the tools may quite practical.

be set off an amount equal to the angle of the tool teeth, to produce a uniform surface throughout the length of the gear teeth. The tools may be offset slightly from such true angular relation to produce a wear on either or both side edges o-f the teeth, of the shape and-form of the teeth but of slightly less width, to permit the meshing of the teeth without interference when they are shifted longitudinally of each other into and out of mesh. The supports for the tools are such that they may be readily set off at any angle so that this particular method of machining gears to have the relief at the side edges of the teeth is It is to-be understood that a suitable lapping compound is disposed between the laps and the gears which may be applied in any manner, either manually or when of suiiicient fluidity by a pumping system during the operation of the machine. The laps are made of cast iron or other metal well known for its resistance to Wear in the presence of the lapping compound.

It is to be understood that, when desirable, the lapping compound can be entirely omitted and a burnishing loperation effected by the machine and also, when desirable, gear like cutting tools as illustrated and described in my copending application, Serial No. 588,635. filed January 25, 1932, and assigned to the assignee of the present invention, may be employed for shaving the teeth to accurate predetermined dimensions. 'Ihe present machine, therefore, is not limited to a lapping operation, as primarily disclosed in the present description, but is equally effective for producing a burnishing operation and also a shaving operation when burnishing and/or shaving tools are substituted for the lapping tools.

While I have illustrated and described but a single embodiment of my invention, it will be apparent to those skilled in the art that various changes, omissions, additions and substitutions may be made therein without departing from the spirit and scope of my invention, as set forth in the accompanying claims.

I claim as my invention:

1. The combination in a gear lapping machine for finishing gears after hardening, of a recipro cable table for supporting a gear to be lapped, a yoke bridging said table, a plurality of pivotally mounted spindles on said yoke, gear-like lapping tools mounted on said spindles having teeth mated with the teeth of said gear and mounted forrotation in different planes which are disposed at an angle to the axis of the gear, means for rotating the gear for driving said lapping tools, and means for reciprocating said table during said gear rotation. l

2. The combination in a gear lapping machine for finishing gears after hardening, of a reciprocable table for supporting a gear to be lapped on an axis about which the gear rotates, a yoke bridging said table, a plurality of pivotally mountedl spindles on said yoke, gear-like lapping tools mounted on said spindles having teeth mated with the teeth of said gear, said tools operating in different planes which are disposed at an angle to the axis of said gear, means for rotating the gear for driving said lapping tools, means for reciprocating said table during said gear rotation,

and means for reversing the rotation of said gear like spiral lapping tools having teeth mated with the teeth of said gear and mounted to rotate in diierent planes which are disposed at an angle to the axis of said gear, means for eiecting the rotation of the gear and said lapping tools, and

means for moving one of the tools from the fin-- ished gear to permit the gear to be removed without disturbing the other tools.

4. The combination in a gear iinishing machine for operating on roughed out gears to machine the teeth to finished dimensions, of means for supporting a roughed out gear to be machined on an axis about which the gear rotates, a plurality of gear-like finishing tools having teeth mated with the teeth of said gear and disposed to rotate in different planes and at an angle to the said axis of the gear, means for effecting the rotation of the gear relative to the finishing tools, and means for moving one of the tools away from said gear Without changing the adjusted position of said tool.

5. The combination in a gear finishing machine for machining the teeth of gears to nished dimensions, of a yoke, a plurality of pivotal supports on each'yoke, machining tools mounted on said supports, means for adjusting said supports angularly to dispose said tools in predetermined angular relation to the gear, a reciprocable table for supporting said gear in rotation in position to be engaged by said tools, means for reciprocating said table, means for rotating said gear and machine tools relative to each other, automatic means for reversing the direction of rotation of said gear and tools, and means for stopping the machine thereafter.

6. The combination in a device for machining the teeth of gears to nished dimensions, of means for rotatably supporting said gear, means for moving said gear axially, tool supports which are angularly adjustable to have the teeth of the machine tools mate with the teeth of the gear, tools on said supports, driving means for effect-ing Ithe rotation of said gear and tools, and control engageable with said gear to be machined, means for driving said gear and tools, and means on said machine for controlling the driving of said gear and tool a4 predetermined number of cycles of operation and for stopping the machine thereafter.

8. The combination in a device for machining the teeth of gears to nished dimensions, of a machine bed for supporting a yoke of inverted U-shape, Ways on said bed, a table mounted for reciprocal movement on said ways between the legs of said yoke, means on said table for rotatably mounting a gear to be machined, a plurality of tool mounting means on said yoke which are adjustable angularly, tools on said means engageable with said gears to be machined, means for raising one of said supports and tools to permit the removal and insertion of said gear Without changing its position of adjustment, and locking means for retaining said tool in adjusted engagement with said gear.

9. The combination in a device for machining the teeth of gears to nished dimensions, of a machine Vbed for supporting a yoke of inverted U- shape, ways on said bed, a table mounted for reciprocal movement on said ways between the legs of said yoke, means on said table for rotatably mounting a gear to be machined., a plurality of tool mounting means on said yoke which are adjustable angularly, tools on said means engageable with said gears to be machined, means for raising one of said supports and tools to permit the removal and insertion of said gear, locking means for retaining said tool in engagement with said gear, and brake mechanism on each of said tool supports for applying a load to the tool.

10. The combination in a device for machining the teeth of gears to finished dimensions, of a machine bed for supporting a yoke of inverted U-shape, ways on said bed, a table mounted for reciprocal movement on said ways between the legs of said yoke, means on said table for rotatably mounting a gear to be machined, a plurality of tool mounting means on said yoke which are adjustable angularly, tools on said means engageable with said gears to be machined, brake mechanism on each of said tool supports for applying a load to the tool, and means for individually regulating the load on each of said tools.

l1. A machine for finishing teeth of gears to accurate form including, in combination, a supporting bed, a reciprocable table mounted thereon, an arbor supported on said table for retaining a gear to be machined for rotational movement, a plurality of arbors pivotallymounted and positionable parallel to said gear arbor and angularly thereto and to each other, machining tools on said arbors in mated relation with said gear, and means for driving said gear in rotation and said table in reciprocation.

ERNEST A. O-VERS'I'EDTv 

